Display device and manufacturing method thereof

ABSTRACT

A display device is provided. The display device includes a display panel, a flexible circuit board, an integrated circuit, and a conductive layer. The flexible circuit board is electrically connected with the display panel and includes a plurality of conductive wires. The integrated circuit is disposed on the flexible circuit board and has a plurality of bumps. The conductive layer is disposed between the integrated circuit and the flexible circuit board and covers a periphery of the integrated circuit. In addition, the conductive layer includes an adhesive and a plurality of conductive particles distributed in the adhesive. Moreover, the bumps are electrically connected with the conductive wires through the conductive particles.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serialno. 201710150979.4, filed on Mar. 14, 2017. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND 1. Technical Field

The disclosure relates to a device and a manufacturing method of thedevice, and particularly relates to a display device and a manufacturingmethod of the display device.

2. Description of Related Art

With the advantages of liquid crystal display panels, such as beingsmall-sized and having low radiation, liquid crystal display deviceshave been broadly applied in various electronic products. In order todisplay an image, a liquid crystal display device requires an integratedcircuit (IC) to drive the liquid crystal display panel. The ICs in theconventional liquid crystal display devices are mostly bonded with theliquid crystal display panels by means of the technique of chip on film(COF). In a conventional COF process, an IC is normally soldered to aflexible printed circuit board (FPCB) by performing high-temperaturelead-tin soldering, and then the FPCB is integrated with the liquidcrystal display panel. Thus, in a conventional manufacturing process ofthe liquid crystal display device, the FPCB encapsulating the IC isnormally acquired through purchasing. Therefore, the limitedspecification of the FPCB makes the FPCB difficult to integrate andincreasing the manufacturing cost.

SUMMARY

The disclosure provides a display device and a manufacturing method ofthe display device to cope with the issues in the prior art.

A display device according to an embodiment of the disclosure includes adisplay panel, a flexible circuit board, an integrated circuit, and aconductive layer. The flexible circuit board is electrically connectedwith the display panel and includes a plurality of conductive wires. Theintegrated circuit is disposed on the flexible circuit board and has aplurality of bumps. The conductive layer is disposed between theintegrated circuit and the flexible circuit board and covers a peripheryof the integrated circuit. In addition, the conductive layer includes anadhesive and a plurality of conductive particles distributed in theadhesive. Moreover, the bumps are electrically connected with theconductive wires through the conductive particles.

A display device according to an embodiment of the disclosure includes adisplay panel, a flexible circuit board, and an integrated circuit. Theflexible circuit board is electrically connected with the display paneland includes a plurality of conductive wires. In addition, a thicknessof at least one of the conductive wires is less than or equal to 3 μm,at least one of the conductive wires includes an extending portion witha width in a range from 1 μm to 7 μm. The integrated circuit is disposedon the flexible circuit board. Moreover, the integrated circuit has aplurality of bumps electrically connected with the conductive wires.

A manufacturing method of a display device according to an embodiment ofthe disclosure includes steps as follows: providing a flexible circuitboard including a plurality of conductive wires manufactured byperforming a thin-film photolithography process, wherein a thickness ofat least one of the conductive wires is less than or equal to 3 μm, theat least one of the conductive wires includes an extending portion witha width in a range from 1 μm to 7 μm; electrically connecting theflexible circuit board and a display panel; electrically connecting theflexible circuit board and an integrated circuit.

In order to make the aforementioned and other features and advantages ofthe disclosure comprehensible, several exemplary embodiments accompaniedwith figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments of thedisclosure and, together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a schematic top view illustrating a display device accordingto an embodiment of the disclosure.

FIG. 2 is a schematic top view illustrating the display device of FIG. 1omitting an insulating layer.

FIG. 3 is a schematic cross-sectional view along a cross-sectional lineI-I′ of FIG. 1.

FIG. 4 is a schematic cross-sectional view along a cross-sectional lineJ-J′ of FIG. 1.

FIG. 5 is a schematic cross-sectional view along a cross-sectional lineK-K′ of FIG. 1.

FIGS. 6A-6D are cross-sectional views illustrating a manufacturingmethod, and the cross-sectional views are taken along thecross-sectional line J-J′ of FIG. 1.

FIGS. 7A-7C are cross-sectional views illustrating a manufacturingmethod, and the cross-sectional views are taken along thecross-sectional line K-K′ of FIG. 1.

FIG. 8 is a partial schematic top view illustrating conductive wires ofFIG. 2.

FIG. 9 is a partial schematic cross-sectional view illustrating adisplay device according to another embodiment of the disclosure,wherein a cross-section of FIG. 9 is based on the cross-sectional lineI-I′ of FIG. 1.

FIG. 10 is a partial schematic cross-sectional view illustrating adisplay device according to another embodiment of the disclosure,wherein a cross-section of FIG. 10 is based on the cross-sectional lineJ-J′ of FIG. 1.

FIG. 11 is a partial schematic cross-sectional view illustrating adisplay device according to another embodiment of the disclosure,wherein a cross-section of FIG. 11 is based on the cross-sectional lineK-K′ of FIG. 1.

DESCRIPTION OF THE EMBODIMENTS

In the disclosure, wherever possible, identical or similar referencenumerals serve to refer to identical or similar components in thedrawings and descriptions.

In the disclosure, the description that a structure is formed on orabove another structure may include an embodiment where the structureand the another structure directly contact each other as well as anembodiment where an additional structure is formed between the structureand the another structure so the structure and the another structure donot directly contact each other.

FIG. 1 is a schematic top view illustrating a display device accordingto an embodiment of the disclosure. FIG. 2 is a schematic top viewillustrating the display device of FIG. 1 omitting an insulating layer.FIG. 3 is a schematic cross-sectional view along a cross-sectional lineI-I′ of FIG. 1. FIG. 4 is a schematic cross-sectional view along across-sectional line J-J′ of FIG. 1. FIG. 5 is a schematiccross-sectional view along a cross-sectional line K-K′ of FIG. 1.

Referring to FIGS. 1 to 5 at the same time, a display device 10 mayinclude a display panel 100, a flexible circuit board 110, an integratedcircuit 120, a conductive layer 130, a conductive layer 140, and aprinted circuit board (PCB) 150. In the present embodiment, the displaydevice 10 may be a liquid crystal (LC) display device, an inorganiclight emitting diode (LED) display device, an organic light emittingdiode (OLED) display device, a mini light emitting diode (mini LED)display device, a micro light emitting diode (micro LED) display device,a quantum dot (QD) display device, a flexible display device, a touchdisplay device or a curved surface display device. However, thedisclosure is not limited thereto. Also, the display panel 100 may be aliquid crystal display panel, an inorganic light emitting diode (LED)display panel, an organic light emitting diode display panel, a minilight emitting diode (mini LED) display device, a micro light emittingdiode display panel, a quantum dot display panel, a touch display panel,or a curved surface display panel. In examples, the chip size of thelight-emitting diode is in a range from about 300 μm to 10 mm, the chipsize of the mini light-emitting diode is in a range from about 100 μm to300 μm, and the chip size of the micro light-emitting diode is in arange from about 1 μm to 100 μm. Nevertheless, the disclosure is notlimited thereto. Specifically, in the present embodiment, the displaypanel 100 may be any kind of liquid crystal display panel known bypeople having ordinary skills in the art. As shown in FIG. 3, in thepresent embodiment, the display panel 100 at least includes a substrate102 and a plurality of pads 104 disposed on the substrate 102. Thematerial of the substrate 102 may include glass, quartz, an organicpolymer, or metal, etc. In practice, in a case when the material of thesubstrate 102 includes an organic polymer, the organic polymer mayinclude (but is not limited to) polyimide (PI), polyethyleneterephthalate (PET), or polycarbonate (PC), etc.

In the present embodiment, the printed circuit board 150 may be any kindof printed circuit board known by people having ordinary skills in theart, such as a flexible printed circuit board or a rigid printed circuitboard.

In the present embodiment, the integrated circuit 120 may be any kind ofintegrated circuit known by people having ordinary skills in the art. Asshown in FIG. 5, in the present embodiment, the integrated circuit 120at least has a plurality of bumps 122. The material of the bump 122 mayinclude a conductive metal, such as (but is not limited to) gold,copper, or aluminum.

In the present embodiment, the flexible circuit board 110 may include adisplay panel bonding area A, a wiring area B, an integrated circuitbonding area C, and a printed circuit board bonding area D. In addition,the wiring area B is located at a side of the display panel bonding areaA and a side of the printed circuit board bonding area D, and the wiringarea B surrounds the integrated circuit bonding area C. In the presentembodiment, the flexible circuit board 110 may include a flexiblesubstrate 112 and a plurality of conductive wires 114, a plurality ofconductive wires 116, and an insulating layer 118 disposed on theflexible substrate 112. In the present embodiment, the material of theflexible substrate 112 may include (but is not limited to) polyimide(PI), polyethylene terephthalate (PET), or polycarbonate (PC), etc.

In the present embodiment, the material of at least one of theconductive wires 114 includes, for example, a conductive materialincluding (but is not limited to) a conductive metal, such as aluminum,copper, titanium, molybdenum, gold, silver, nickel, or an alloy thereof;or a metal oxide such as indium-tin-oxide (ITO), indium zinc oxide(IZO), aluminum tin oxide (ATO), aluminum zinc oxide (AZO), or indiumgallium zinc oxide (IGZO). In the present embodiment, the thickness ofat least one of the conductive wires 114 is less than or equal to 3 μm.In the present embodiment, the conductive wires 114 extend from theintegrated circuit bonding area C to the display panel bonding area Athrough the wiring area B. Namely, the conductive wires 114 are locatedin the integrated circuit bonding area C, the wiring area B, and thedisplay panel bonding area A. Specifically, in the present embodiment,the conductive wires 114 include a display panel pad portion 114 a, anintegrated circuit pad 114 c, and an extending portion 114 b connectingthe display panel pad portion 114 a to the integrated circuit pad 114 c.It should be noted that as long as at least one of the conductive wires114 includes the display panel pad portion 114 a, the integrated circuitpad 114 c, and the extending portion 114 b, the above falls within thescope of the present disclosure. More specifically, in the presentembodiment, as shown in FIG. 3, the display panel pad portion 114 a islocated in the display panel bonding area A and corresponds to the pads104 of the display panel 100, and as shown in FIG. 5, the integratedcircuit pad 114 c is located in the integrated circuit bonding area Cand corresponds to the bumps 122 of the integrated circuit 120.Specifically, in an embodiment, a width Wc or a width Wb is in a rangefrom 1 μm to 40 μm. In another embodiment, the width Wb is in a rangefrom 1 μm to 7 μm. In another embodiment, the width Wb is 5 μm. Inanother embodiment, the width Wc is in a range from 3 μm to 20 μm. Inanother embodiment, the width Wc is 15 μm.

In the present embodiment, the conductive wires 116 extend from theintegrated circuit bonding area C to the printed circuit board bondingarea D through the wiring area B. Namely, the conductive wires 116 arelocated in the integrated circuit bonding area C, the wiring area B, andthe printed circuit board bonding area D. It should be noted that, basedon the descriptions about the conductive wires 114, people havingordinary skills in the art shall understand relevant details about thematerial, the structure, and the arrangement of the conductive wires116. In other words, the material, the structure, and the arrangement ofthe conductive wires 116 may be the same as those of the conductivewires 114. Besides, even though the embodiment in FIGS. 1 to 5 showsthat the number of each of the conductive wires 114 and the conductivewires 116 is four, the disclosure is not limited thereto. In otherembodiments, the numbers, the widths, the pitches, or the shapes of theconductive wires 114 and the conductive wires 116 may be adjusted basedon the practical needs of the display device.

In the embodiment, the insulating layer 118 is disposed in the wiringarea B, and the insulating layer 118 covers the conductive wires 114 andthe conductive wires 116. Accordingly, the insulating layer 118 is ableto protect the conductive wires 114 and the conductive wires 116 frombeing damaged by moisture. Specifically, in the present embodiment, thematerial of the insulating layer 118 may include a moisture-proofinsulating material, such as (but is not limited to): a photoresist, asolder resist, AlN_(x), SiO_(x), or SiN_(x). Besides, in the presentembodiment, the insulating layer 118 is not disposed in the integratedcircuit bonding area C, the display panel bonding area A, and theprinted circuit bonding area D. Accordingly, the display panel padportion 114 a and the integrated circuit pad 114 c are not covered bythe insulating layer 118 and are exposed.

In the present embodiment, the conductive layer 130 is disposed betweenthe integrated circuit 120 and the flexible circuit board 110. In thepresent embodiment, the conductive layer 130 covers the periphery of theintegrated circuit 120. However, the disclosure is not limited thereto.Besides, in the present embodiment, the conductive layer 130 includes anadhesive 132 and a plurality of conductive particles 134 distributed inthe adhesive 132. As shown in FIG. 5, in the present embodiment, thebumps 122 of the integrated circuit 120 are electrically connected withthe integrated circuit pads 114 c of the conductive wires 114 throughthe conductive particles 134, and the integrated circuit 120 is adheredto the flexible circuit board 110 through the adhesive 132. In otherwords, the conductive layer 130 serves to electrically and physicallyconnect the integrated circuit 120 and the flexible circuit board 110.More specifically, in the present embodiment, the integrated circuit 120and the flexible circuit board 110 are electrically connected becausethe conductive particles 134 between the bumps 122 and the integratedcircuit pads 114 c are pressed and deformed, thereby being electricallyconductive. Accordingly, in the embodiment, gaps are provided betweenthe bumps 122 and the integrated circuit pads 114 c, and each ofconductive paths between the bumps 122 and the integrated circuit pads114 c may be discontinuous. In other embodiments, each of the conductivepaths between the bumps 122 and the integrated circuit pads 114 c may bepartially continuous. In the present embodiment, a conductive path maybe a path that one of the bumps 122 is electrically connect with one ofthe integrated circuit pads 114 c through one of the conductiveparticles 134. When the conductive particles 134 discontinuously (orseparately) disposed between the bumps 122 and the integrated circuitpads 114 c, the conductive paths may be discontinuous. However, thedisclosure is not limited thereto. Specifically, in the presentembodiment, the conductive layer 130 may be an anisotropic conductivefilm (ACF). The material of the adhesive 132 may include (but is notlimited to) a thermosetting polymer material or a thermoplastic polymermaterial, for example. The material of the conductive particles 134 mayinclude (but is not limited thereto) gold, nickel, tin, or palladium,for example.

Besides, in the present embodiment, even though FIG. 5 illustrates thatthe integrated circuit pads 114 c and the bumps 122 have the same width,the disclosure is not limited thereto. In other embodiments, theintegrated circuit pads 114 c and the bumps 122 may have differentwidths. For example, in an embodiment, the width of the integratedcircuit pads 114 c may be greater than the width of the bumps 122. Asanother example, in an embodiment, the width of the integrated circuitpads 114 c may be smaller than the width of the bumps 122. In thepresent embodiment, even though FIG. 5 illustrates that the integratedcircuit pads 114 c and the bumps 122 are aligned to each other, thedisclosure is not limited thereto. In other embodiments, the integratedcircuit pads 114 c and the bumps 122 may have the same width, but thepositions of the integrated circuit pads 114 c and the bumps 122 arestaggered or deviated, or the integrated circuit pads 114 c and thebumps 122 may have different widths, and the positions of the integratedcircuit pads 114 c and the bumps 122 are staggered or deviated.

In the present embodiment, the conductive layer 140 is disposed betweenthe display panel 100 and the flexible circuit board 110. In the presentembodiment, the conductive layer 140 includes an adhesive 142 and aplurality of conductive particles 144 distributed in the adhesive 142.As shown in FIG. 3, in the present embodiment, the pads 104 of thedisplay panel 100 are electrically connected with the display panel padportions 114 a of the conductive wires 114 through the conductiveparticles 144, and the display panel 100 is adhered to the flexiblecircuit board 110 through the adhesive 142. In other words, theconductive layer 140 is able to electrically and physically connect thedisplay panel 100 and the flexible circuit board 110. More specifically,in the embodiment, the display panel 100 and the flexible circuit board110 are electrically connected because the conductive particles 144between the pads 104 and the display panel pad portions 114 a arepressed and deformed, thereby being electrically conductive. However,the disclosure is not limited thereto. Specifically, in the presentembodiment, the conductive layer 140 may be an anisotropic conductivefilm (ACF). The material of the adhesive 142 may include (but is notlimited to) a thermosetting polymer material or a thermoplastic polymermaterial, for example. The material of the conductive particles 144 mayinclude (but is not limited thereto) gold, nickel, tin, or palladium,for example.

From another perspective, in the present embodiment, the display panel100 and the integrated circuit 120 may be electrically connected witheach other through the flexible circuit board 110. In the presentembodiment, the flexible circuit board 110 may be a chip-on-film (COF).In other words, the integrated circuit 120 in the display device 10 maybe electrically connected with the display panel 100 by means of COF.

In addition, based on the descriptions about the connection between theintegrated circuit 120 and the flexible circuit board 110 through theconductive wires 114 and the connection between the display panel 100and the flexible circuit board 110 through the conductive wires 114,people having ordinary skills in the art shall understand the connectionbetween the integrated circuit 120 and the flexible circuit board 110through the conductive wires 116 and the connection between the printedcircuit board 150 and the flexible circuit board 110 through theconductive wires 116. In other words, in the present embodiment, thebumps 122 of the integrated circuit 120 are also electrically connectedwith the integrated circuit pads of the conductive wires 116 through theconductive particles 134, and the pads of the printed circuit board 150are also electrically connected with the display panel pad portions ofthe conductive wires 116 through the conductive particles.

It should be noted that the integrated circuit 120, the flexible circuitboard 110, the printed circuit board 150, and the display panel 100 areelectrically connected with each other, as mentioned above. The bumps122 of the integrated circuit 122 may transmit a signal received fromthe printed circuit board 150 into the integrated circuit 120 for signalprocessing, and then transmit the processed signal to the display panel100. Accordingly, sub-pixels (e.g., red, green, and blue sub-pixels) inthe display panel 100 may display correct levels of color.

Besides, based on the descriptions about FIGS. 1 to 5, people havingordinary skills in the art shall understand that the integrated circuit120 may also be electrically connected with the conductive wires 116through a conductive layer, the printed circuit board 150 may also beelectrically connected with the flexible circuit board 110 through aconductive layer, and the printed circuit board 150 and the integratedcircuit 120 may also be electrically connected with each other throughthe flexible circuit board 110.

It is noteworthy that, in the display device 10 of the presentembodiment, the bumps 122 of the integrated circuit 120 are electricallyconnected with the conductive wires 114 of the flexible circuit board110 through the conductive particles 134 in the conductive layer 130.Thus, a process of bonding the integrated circuit 120 and the flexiblecircuit board 110 may be performed based on a manufacturing techniquefor manufacturing the display panel 100, and a process ofhigh-temperature lead-tin soldering is thus not required to bond theintegrated circuit and the flexible circuit board.

Moreover, in the display device 10 of the embodiment, the conductivewires 114 may have the thickness less than or equal to 3 μm, and theextending portions 114 b of the conductive wires 114 may have the widthin a range from 1 μm to 7 μm. Accordingly, compared with theconventional flexible circuit board, the display device 10 is moreapplicable to a small-sized electronic device or a high-resolutiondisplay device.

Generally speaking, in a conventional COF process, a conductive wire ismanufacturing by electroplating. Thus, the thickness and the width ofthe conductive wire are limited. The thickness of the conductive wiremanufactured by electroplating is in a range from about 6 μm to 10 μm,and the width of the conductive wire manufactured by electroplating isapproximately equal to or greater than 10 μm. It should be noted that,in the present embodiment, the conductive wires 114 are manufactured byperforming a thin-film photolithography process. Thus, the thickness andthe width of the conductive wires 114 may be reduced. The conductivewires 114 may have the thickness smaller than or equal to 3 μm and thewidth in a range from 1 μm to 7 μm. In the following, a manufacturingmethod of the display device 10 is described.

In the embodiment, the manufacturing method of the display device 10 mayinclude steps as follows. The flexible circuit board 110 is provided.The flexible circuit board 110 is electrically connected with theintegrated circuit 120. The flexible circuit board 110 and the displaypanel 100 are electrically connected. The flexible circuit board 110 andthe printed circuit board 150 are electrically connected.

First, the step of providing the flexible circuit board 110 is describedwith reference to FIGS. 6A to 6D. FIGS. 6A-6D are cross-sectional viewsillustrating a manufacturing method, and the cross-sectional views aretaken along the cross-sectional line J-J′ of FIG. 1.

First, referring to FIG. 6A, a conductive wire material layer 160 isformed on the flexible substrate 112. Specifically, a process of formingthe conductive wire material layer 160 may include (but is not limitedto) performing a sputtering process or a metal organic chemical vapordeposition (MOCVD) process, for example. In the present embodiment, thematerial of the conductive wire material layer 160 includes, forexample, a conductive material including (but is not limited to) aconductive metal, such as aluminum, copper, titanium, molybdenum, gold,silver, nickel, or an alloy thereof; or a metal oxide such asindium-tin-oxide (ITO), indium zinc oxide (IZO), aluminum tin oxide(ATO), aluminum zinc oxide (AZO), or indium gallium zinc oxide (IGZO).

Then, a patterned photoresist layer 170 is formed on the conductive wirematerial layer 160. Specifically, in the present embodiment, a processof forming the patterned photoresist layer 170 may include steps asfollows: after forming a photoresist layer (not shown) on the conductivewire material layer 160, sequentially performing an exposure process anda development process. A process of forming the photoresist layer mayinclude (but is not limited to) performing a wet coating process, suchas spin coating, roll coating, blade coating, slide coating, slot-diecoating, or wire bar coating.

Then, referring to FIG. 6B, using the patterned photoresist layer 170 asa mask, a portion of the conductive wire material layer 160 is removedto form the extending portions 114 b of the conductive wires 114. Itshould be noted that, while FIG. 6B only illustrates a cross-sectionalview along the cross-sectional line J-J′, people having ordinary skillsin the art shall understand based on the descriptions of FIGS. 1 to 5that the display panel pad portions 114 a and the integrated circuitpads 114 c are also formed when the extending portions 114 b are formed.In other words, at the step shown in FIG. 6B, the conductive wires 114are formed on the flexible substrate 112. Besides, in the presentembodiment, a process of removing a portion of the conductive wirematerial layer 160 may include (but is not limited to) performing a wetetching process, a dry etching process, or a combination thereof.

Then, referring to FIG. 6C, the patterned photoresist layer 170 isremoved. Specifically, in the present embodiment, a process of removingthe patterned photoresist layer 170 may include (but is not limited to)performing a wet-type process adopting a peeling solution, or a dry-typeprocess adopting plasma ashing.

Then, referring to FIG. 6D, the insulating layer 118 is formed on theflexible substrate 112. Specifically, in the present embodiment, aprocess of forming the insulating layer 118 may include (but is notlimited to) performing a wet coating process, such as spin coating, rollcoating, blade coating, slide coating, slot-die coating, or wire-barcoating.

Besides, based on the descriptions of FIGS. 1 to 5, people havingordinary skills in the art shall understand that, before forming theinsulating layer 118 on the flexible substrate 112, the conductive wires116 are formed on the flexible substrate 112, and the insulating layer118 is disposed on a portion of the conductive wires 116. Morespecifically, based on the descriptions of FIGS. 1 to 5 and FIGS. 6A to6C, people having ordinary skills in the art shall understand a processof forming the conductive wires 116 on the flexible substrate 112.

Then, the step of electrically connecting the flexible circuit board 110and the integrated circuit 120 is described with reference to FIGS. 7Ato 7C. FIGS. 7A-7C are cross-sectional views illustrating amanufacturing method, and the cross-sectional views are taken along thecross-sectional line K-K′ of FIG. 1.

First of all, referring to FIG. 7A, the conductive layer 130 is disposedon the integrated circuit pads 114 c of the conductive wires 114 in theintegrated circuit bonding area C. Specifically, in the embodiment, aprocess of disposing the conductive layer 130 on the integrated circuitpads 114 c includes attaching the conductive layer 130 on the integratedcircuit pads 114 c, for example.

Then, referring to FIG. 7B, a pre-bonding process is performed topre-align the flexible circuit board 110 with the integrated circuit120. Specifically, in the embodiment, when the pre-bonding process isperformed, since the adhesive 132 in the conductive layer 130 isadhesive, the integrated circuit 120 may be pre-bonded to the flexiblecircuit board 110 through the conductive layer 130.

Then, referring to FIG. 7C, a thermal compression process is performedto fix the conductive layer 130 between the flexible circuit board 110and the integrated circuit 120. Specifically, in the embodiment, acondition of temperature of the thermal compression process is in arange from 100° C. to 200° C., for example, and a condition of pressureof the thermal compression process is in a range from 10 MPa to 120 MPa,for example. After being soldered to the chip-on-film throughhigh-temperature lead-tin soldering, an underfill also needs to beadditionally disposed to the conventional integrated circuit toreinforce bonding between the integrated circuit and the chip-on-filmand to block moisture or an external object, so as to protect the bumpsand the integrated circuit pads. In the embodiment, after the thermalcompression process, the conductive layer 130 may surround the peripheryof the integrated circuit 120 to cover the bumps 122 and the integratedcircuit pads 114 c of the integrated circuit 120. Accordingly, while thehigh-temperature lead-tin soldering and the underfill are not requiredto be disposed between the flexible circuit board 110 and the integratedcircuit 120 in the embodiment, the electrical connection, reinforcementof bonding, and blocking of moisture and external object can still beachieved.

Then, referring to FIGS. 1 and 3, the flexible circuit board 110 and thedisplay panel 100 are electrically connected. Based on the descriptionsabout FIG. 3, it can be known that the flexible circuit board 110 andthe display panel 100 are electrically connected through the conductivelayer 140. Therefore, based on the descriptions about FIGS. 7A to 7C,people having ordinary skills in the art shall understand how theflexible circuit board 110 and the display panel 100 are electricallyconnected.

Then, referring to FIG. 1, the flexible circuit board 110 and theprinted circuit board 150 are electrically connected. Based on thedescriptions about FIGS. 1 to 5 and FIGS. 7A to 7C, people havingordinary skills in the art shall understand how the flexible circuitboard 110 and the printed circuit board 150 are electrically connected.

It should be noted that, in the manufacturing method of the displaydevice 10, the conductive wires 114 of the flexible circuit board 110are manufactured by performing a thin-film photolithography process.Therefore, the flexible circuit board 110 can be manufactured by using aprocessing technique commonly used in the manufacture of the displaypanel 100, and therefore the flexible circuit board 110 is not requiredto be additionally purchased. Thus, compared with the conventionaldisplay device requiring additionally purchasing the flexible circuitboard during the manufacturing process, the display device 10 is moreflexible in manufacturing and has a lower manufacturing cost.

Besides, even though the manufacturing method of the display device 10is described with the following order: electrically connecting theflexible circuit board 110 and the integrated circuit 120, electricallyconnecting the flexible circuit board 110 and the display panel 100, andelectrically connecting the flexible circuit board 110 and the printedcircuit board 150, the disclosure is not limited by the order. In otherwords, the manufacturing method of the display device 10 of thedisclosure is not limited by the aforementioned order, and the orderamong electrically connecting the flexible circuit board 110 and theintegrated circuit 120, electrically connecting the flexible circuitboard 110 and the display panel 100, and electrically connecting theflexible circuit board 110 and the printed circuit board 150 isvariable.

As shown in FIGS. 4 and 5, the width Wc of the integrated circuit pads114 c is greater than the width Wb of the extending portions 114 b inthe embodiment. In the following, a structural relation between theintegrated circuit pads 114 c and the extending portions 114 b isdescribed in greater detail with reference to FIG. 8.

FIG. 8 is a partial schematic top view illustrating conductive wires ofFIG. 2. It should be noted that FIG. 8 correspondingly illustrates aportion of the conductive wires 114 corresponding to the wiring area Band the integrated circuit bonding area C.

Referring to FIG. 8, the width Wc of the integrated circuit pads 114 cis greater than the width Wb of the extending portions 114 b.Specifically, in an embodiment, the width Wc of the integrated circuitpads 114 c is in a range from 1 μin to 40 μm. In another embodiment, thewidth Wc of the integrated circuit pads 114 c is in a range from 3 μm to20 μm. In another embodiment, the width Wc of the integrated circuitpads 114 c is 15 μm. Also, in an embodiment, a length Lc of theintegrated circuit pads 114 c is in a range from 1 μm to 60 μm. Inanother embodiment, the length Lc of the integrated circuit pads 114 cis in a range from 3 μm to 50. In yet another embodiment, the length Lcof the integrated circuit pads 114 c is 40 μm. Furthermore, in anembodiment, the width Wb of the extending portions 114 b is in a rangefrom 1 to 40 μm. In another embodiment, the width Wb of the extendingportions 114 b is in a range from 1 μm to 7 μm. In another embodiment,the width Wb of the extending portions 114 b is 5 μm.

It should be noted that the integrated circuit pads 114 c of thedisclosure are electrically connected with the integrated circuit 120through the conductive layer 130. Therefore, in the embodiment, sincethe width Wc of the integrated circuit pads 114 c is greater than thewidth Wb of the extending portions 114 b, a contact area between theintegrated circuit pads 114 c and the conductive layer is increased.Thus, the number of conductive particles captured by the integratedcircuit pads 114 c is increased, so the resistance is reduced, and theconducting capability is increased.

Besides, in the embodiment, integrated circuit pads 114 c of adjacentconductive wires 114 are deviated from each other. In other words, inthe embodiment, from a top perspective, the integrated circuit pads 114c of the conductive wires 114 are not at the same horizontal position.Specifically, in an embodiment, a distance D1 between the integratedcircuit pad 114 c of one of the conductive wires 114 and the extendingportion 114 b of the conductive wire 114 adjacent to the one of theconductive wires 114 is in a range from 1 μm to 30 μm. In anotherembodiment, the distance D1 is in a range from 2 μm to 10 μm. In yetanother embodiment, the distance D1 is 9 μm. In addition, in anembodiment, a distance D2 between the integrated circuit pad 114 c ofone of the conductive wires 114 and the integrated circuit pad 114 c ofthe conductive wire 114 adjacent to the one of the conductive wires 114is in a range from 1 μm to 30 μm. In another embodiment, the distance D2is in a range from 5 μm to 28 μm. In yet another embodiment, thedistance D2 is 22 μm.

It should be noted that, in the embodiment, by making the integratedcircuit pads 114 c of the adjacent conductive wires 114 deviated fromeach other, the conductive wires 114 are still disposed tightly to savethe space even though the width Wc of the integrated circuit pads 114 cis greater than the width Wb of the extending portions 114 b.

Moreover, even though the width Wc of the integrated circuit pads 114 cis greater than the width Wb of the extending portions 114 b in theembodiment of FIG. 8 to increase the contact area between the integratedcircuit pads 114 c and the conductive layer, the disclosure is notlimited thereto. In other embodiments, the width Wc of the integratedcircuit pads 114 c may also be the same as the width Wb of the extendingportions 114 b. Besides, in the embodiment of FIG. 8, the extendingportion 114 b has the uniform width Wb. However, the disclosure is notlimited thereto. In other embodiments, the width of the extendingportion 114 b may be varied. For example, the extending portion 114 bhas two ends, and the width of the extending portion 114 b may begradually decreased from one end connecting the display panel padportion 114 a to the other end connecting the integrated circuit pad 114c.

Besides, in the embodiment of FIGS. 1 and 4, the insulating layer 118 isfilled between the adjacent conductive wires 114 in the wiring area B ofthe flexible circuit board 110. However, the disclosure is not limitedthereto. In other embodiments, other components may be disposed betweenthe adjacent conductive wires 114. In the following, details in thisrespect will be described with reference to FIGS. 9 to 11.

FIGS. 9, 10, and 11 are respectively partial schematic cross-sectionalviews illustrating a display device according to another embodiment ofthe disclosure, wherein a cross-section shown in FIG. 9 is based on thecross-sectional line I-I′ of FIG. 1, a cross-section shown in FIG. 10 isbased on the cross-sectional line J-J′ of FIG. 1, and a cross-sectionshown in FIG. 11 is based on the cross-sectional line K-K′ of FIG. 1.Hence, a top view of a display device 30 shown in FIGS. 9 to 11 may bereferred to FIGS. 1 and 2. It should be noted that the referencenumerals and a part of the contents in the previous embodiment are usedin the embodiment, in which identical or similar reference numeralsindicate identical or similar components, and repeated description ofthe same technical contents is omitted. For a detailed description ofthe omitted parts, reference can be found in the previous embodiment,and no repeated description is contained in the following embodiments.In the following, the description will focus on the difference betweenthe embodiment of FIGS. 9 to 11 and the embodiment of FIGS. 1 to 5.

Referring to FIGS. 9 to 11, in the embodiment, a flexible circuit board300 includes a plurality of spacers 302 disposed on the flexiblesubstrate 112. Specifically, in the embodiment, as shown in FIG. 9, thespacers 302 and the display panel pad portions 114 a of the conductivewires 114 are disposed alternately. As shown in FIG. 10, the spacers 302and the extending portions 114 b of the conductive wires 114 aredisposed alternately. As shown in FIG. 11, the spacers 302 and theintegrated circuit pads 114 c of the conductive wires 114 are disposedalternately. In other words, in the embodiment, the spacers 302 arelocated in the integrated circuit bonding area C, the wiring area B, andthe display panel bonding area A. In addition, the conductive wire 114is located between two adjacent spacers 302. Besides, in an embodiment,the spacers 302 may extend from the integrated circuit bonding area C tothe printed circuit board bonding area D through the wiring area B.Namely, the spacers 302 may be continuously disposed in the integratedcircuit bonding area C, the wiring area B, and the printed circuit boardbonding area D. Nevertheless, the disclosure is not limited thereto. Inanother embodiment, the spacers 302 may also be discontinuouslydistributed in the printed circuit board bonding area D, the integratedcircuit bonding area C, the wiring area B, and the display panel bondingarea A.

In the embodiment, the material of the spacers 302 may include aninsulating material, such as (but is not limited to) a photoresist,SiN_(x), or SiO_(x). In the embodiment, a process of forming the spacers302 includes performing a thin-film photolithography process, forexample. It should be noted that, based on the descriptions of FIGS. 6Ato 6C, people having ordinary skills in the art shall understand aprocess of forming the spacers 302 on the flexible substrate 112.

It should also be noted that, in the display device 30, the conductivewires 114 and the spacers 302 of the flexible circuit board 300 areformed by performing a thin-film photolithography process, such that theflexible circuit board 300 can be manufactured by using a processingtechnique commonly used in the manufacture of the display panel 110, andis not required to be additionally purchased. Thus, compared with theconventional display device requiring additionally purchasing theflexible circuit board during the manufacturing process, the displaydevice 30 is more flexible in manufacturing and has a lowermanufacturing cost.

In the embodiment, the thickness of the spacers 302 is greater than thethickness of the conductive wires 114 adjacent to the spacers 302.Hence, the spacers 302 are capable of preventing the conductiveparticles 144 in the conductive layer 140 from accumulating between theadjacent conductive wires 114, and thus the probability of short circuitoccurring due to the accumulation of the conductive particles 144between the adjacent conductive wires 114 is reduced.

Specifically, as shown in FIG. 9, there is a thickness difference ΔH1between a maximum thickness of at least one of the spacers 302 in thedisplay panel bonding area A and a thickness of at least one of thedisplay panel pad portions 114 a of the conductive wires 114 adjacent tothe at least one of the spacers 302. Specifically, in the embodiment,the thickness difference ΔH1 satisfies a formula as follows: ΔH1=R(1-X%), wherein R is a diameter of one of the conductive particles 144, X %is a particle size compression rate of one of the conductive particles144 (i.e., a deformation degree of the conductive particle 144 aftercompression), and X % is in a range from 30% to 70%. For example, in anembodiment, when the diameter of the conductive particle 144 is 3 μm,the thickness difference ΔH1 is in a range from about 0.9 μm to about2.1 μm. A formula for calculating the particle size compression rate isas follows: particle size compression rate=(1−√(a/b))×100%, wherein a isa particle diameter in a short axis of one of the conductive particles144 after compression, and b is a particle diameter in a long axis ofone of the conductive particles 144 after compression.

It should be noted that, with the thickness difference ΔH1 between thespacer 302 and the display panel pad portion 114 a of the conductivewire 114 adjacent to the spacer 302 in the display panel bonding area A,the space between the bonded display panel 100 and the bonded flexiblecircuit board 300 is controlled, and the deformation degree of theconductive particles 144 between the pads 104 of the display panel 100and the display panel pad portions 114 a after compression iscontrolled. Therefore, the conductive particles 144 may be preventedfrom cracking. In addition, in the embodiment, with the spacer 302disposed between the adjacent conductive wires 114, the conductiveparticles 144 may be prevented from accumulating between the adjacentconductive wires 114, and thus the probability of short circuitoccurring due to the accumulation of the conductive particles 144between the adjacent conductive wires 114 is reduced.

Besides, as shown in FIG. 11, there is a thickness difference ΔH2between a maximum thickness of at least one of the spacers 302 and athickness of at least one of the integrated circuit pads 114 c of theconductive wires 114 adjacent to the at least one of the spacers 302 inthe integrated circuit bonding area C. Specifically, in the embodiment,the thickness difference ΔH2 satisfies a relation as follows: 1/4h≤ΔH2≤1/2 h, wherein h is a thickness of one of the bumps 122. Forexample, in an embodiment, when the thickness of the bump 122 is 12 μm,the thickness difference ΔH2 is in a range from 3 μm to 6 μm.

It should be noted that, in the embodiment, with the thicknessdifference ΔH2 between the spacer 302 and the integrated circuit pad 114c of the conductive wire 114 adjacent to the spacer 302 in theintegrated circuit bonding area C, when the flexible circuit board 300and the integrated circuit 120 are bonded, the spacer 302 may bedisposed between the adjacent bumps 122 to facilitate the alignmentbetween the integrated circuit pads 114 c and the bumps 122 of theintegrated circuit 120, thereby making the alignment more accurate. Inaddition, with the spacer 302 disposed between the adjacent conductivewires 114, the conductive particles 134 may be prevented fromaccumulating between the adjacent conductive wires 114, and thus theprobability of short circuit occurring due to the accumulation of theconductive particles 134 between the adjacent conductive wires 114 isreduced.

Moreover, as shown in FIG. 10, there is also the thickness differenceΔH1 between the spacer 302 and the extending portion 114 b of theconductive wire 114 adjacent to the spacer 302 in the wiring area B.Nevertheless, the disclosure is not limited thereto. In otherembodiments, there may also be another thickness difference between thespacer 302 and the extending portion 114 b of the conductive wire 114adjacent to the spacer 302 in the wiring area B.

As shown in FIGS. 9 to 11, a top surface of the spacers 302 may have anarc-shaped profile. Nevertheless, the disclosure is not limited thereto.In other embodiments, the top surface of the spacers 302 may also have ataper-shaped profile, a trapezoid-shaped profile, or a profile in othershapes. It should be noted that, in the embodiment, with the top surfaceof the spacers 302 exhibiting such profiles, when the flexible circuitboard 300 and the integrated circuit 120 are bonded and when theflexible circuit board 300 and the display panel 100 are bonded, thespacers 302 may facilitate the conductive particles 134 to move topositions between the bumps 122 of the integrated circuit 120 and theintegrated circuit pads 114 c of the flexible circuit board 300, andfacilitate the conductive particles 144 to move to positions between thepads 104 of the display panel 100 and the display panel pad portions 114a of the flexible circuit board 300, thereby increasing the number ofthe conductive particles therebetween to reduce the resistance andenhance the conducting capability.

In view of the foregoing, the bumps of the integrated circuit areelectrically connected with the conductive wires of the flexible circuitboard through the conductive particles in the conductive layer, so themanufacturing cost of the display device of the disclosure is lower thanthat of the conventional display device. Moreover, the conductive wiresof the flexible circuit board have the thickness less than or equal to 3μm and the width in a range from 1 μm to 7 μm, so the display device ofthe disclosure is more applicable in small-sized electronic devices andbetter copes with the trend than the conventional display device.Moreover, in the manufacturing method of the display device of thedisclosure, the conductive wire in the flexible circuit board ismanufactured by performing a thin-film photolithography process, suchthat the flexible circuit board can be manufactured by using aprocessing technique commonly used in the manufacture the display panel,and is not required to be additionally purchased. Accordingly, comparedwith the conventional display device requiring additionally purchasingthe flexible circuit board, the display device manufactured according tothe manufacturing method of the display device of the disclosure is moreflexible in manufacturing and has a lower manufacturing cost. Besides,the two embodiments for the flexible circuit board proposed in thedisclosure may be used in combination in the display device of thedisclosure. In other words, the spacer may be disposed between theadjacent conductive wires in a portion of the area of the flexiblecircuit board and not disposed in the rest of the area of the flexiblecircuit board.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the present disclosurecovers modifications and variations of this disclosure provided theyfall within the scope of the following claims and their equivalents.

What is claimed is:
 1. A display device, comprising: a display panel; aflexible circuit board, electrically connected with the display panel,and the flexible circuit board comprising a plurality of conductivewires; an integrated circuit, disposed on the flexible circuit board,and the integrated circuit having a plurality of bumps; and a conductivelayer, disposed between the integrated circuit and the flexible circuitboard, and the conductive layer comprising an adhesive and a pluralityof conductive particles distributed in the adhesive, wherein the bumpsare electrically connected with the conductive wires through theconductive particles.
 2. The display device as claimed in claim 1,wherein a thickness of at least one of the conductive wires is less thanor equal to 3 μm.
 3. The display device as claimed in claim 1, whereinthe flexible circuit board comprises a display panel bonding area, anintegrated circuit bonding area, and a wiring area, and the wiring areais located at a side of the display panel bonding area and surrounds theintegrated circuit bonding area.
 4. The display device as claimed inclaim 3, wherein the conductive wires extend from the integrated circuitbonding area to the display panel bonding area through the wiring area.5. The display device as claimed in claim 3, wherein at least one of theconductive wires comprises an integrated circuit pad and an extendingportion connected with the integrated circuit pad, the integratedcircuit pad is located in the integrated circuit bonding area, and awidth of the integrated circuit pad is greater than a width of theextending portion, wherein the width of the integrated circuit pad is ina range from 3 μm to 20 μm, and the width of the extending portion is ina range from 1 μm to 7 μm.
 6. The display device as claimed in claim 1,wherein a conductive path between at least one of the bumps and theintegrated circuit pad is discontinuous.
 7. The display device asclaimed in claim 3, wherein the flexible circuit board further comprisesa plurality of spacers, the spacers and the conductive wires aredisposed alternately, and a thickness of at least one of the spacers isgreater than a thickness of at least one of the conductive wiresadjacent to the at least one of the spacers.
 8. The display device asclaimed in claim 7, wherein a thickness difference ΔH1 between the atleast one of the spacers in the display panel bonding area and at leastone of the conductive wires adjacent to the at least one of the spacerssatisfies a formula as follows: ΔH1=R(1-X %), wherein R is a diameter ofone of the conductive particles, X % is a particle size compression rateof one of the conductive particles, and X % is in a range from 30% to70%.
 9. The display device as claimed in claim 7, wherein a thicknessdifference ΔH2 between the at least one of the spacers in the integratedcircuit bonding area and at least one of the conductive wires adjacentto the at least one of the spacers satisfies a relation as follows: 1/4h≤ΔH2≤1/2 h, wherein h is a thickness of one of the bumps.
 10. Thedisplay device as claimed in claim 3, wherein the flexible circuit boardfurther comprises an insulating layer disposed in the wiring area, andthe insulating layer covers the conductive wires.
 11. A display device,comprising: a display panel; a flexible circuit board, electricallyconnected with the display panel and comprising a plurality ofconductive wires, wherein a thickness of at least one of the conductivewires is less than or equal to 3 μm, at least one of the conductivewires comprises an extending portion, and a width of the extendingportion is in a range from 1 μm to 7 μm; and an integrated circuit,disposed on the flexible circuit board, wherein the integrated circuithas a plurality of bumps electrically connected with the conductivewires.
 12. The display device as claimed in claim 11, further comprisinga conductive layer disposed between the integrated circuit and theflexible circuit board, and the conductive layer comprising an adhesiveand a plurality of conductive particles distributed in the adhesive,wherein the bumps are electrically connected with the conductive wiresthrough the conductive particles.
 13. A manufacturing method of adisplay device, comprising: providing a flexible circuit boardcomprising a plurality of conductive wires, the conductive wiresmanufactured by performing a thin-film photolithography process, whereina thickness of at least one of the conductive wires is less than orequal to 3 μm, the at least one of the conductive wires comprises anextending portion, and a width of the extending portion is in a rangefrom 1 μm to 7 μm; electrically connecting the flexible circuit boardand an integrated circuit; and electrically connecting the flexiblecircuit board and a display panel.
 14. The manufacturing method of thedisplay device as claimed in claim 13, wherein the flexible circuitboard further comprises a plurality of spacers, the spacers and theconductive wires are disposed alternately, and the spacers aremanufactured by performing a thin-film photolithography process.
 15. Themanufacturing method of the display device as claimed in claim 13,wherein the flexible circuit board comprises a display panel bondingarea, an integrated circuit bonding area, and a wiring area, and thewiring area is located at a side of the display panel bonding area, andthe wiring area surrounds the integrated circuit bonding area.
 16. Themanufacturing method of the display device as claimed in claim 15,wherein the at least one of the conductive wires extends from theintegrated circuit bonding area to the display panel bonding areathrough the wiring area.
 17. The manufacturing method of the displaydevice as claimed in claim 15, wherein the step of electricallyconnecting the flexible circuit board and the integrated circuitcomprises: forming a conductive layer on at least one of the conductivewires in the integrated circuit bonding area; performing a pre-bondingprocess to pre-align the flexible circuit board and the integratedcircuit; and performing a thermal compression bonding process to fix theconductive layer between the flexible circuit board and the integratedcircuit.
 18. The manufacturing method of the display device as claimedin claim 15, wherein the at least one of the conductive wires furthercomprises an integrated circuit pad connected with the extendingportion, the integrated circuit pad is located in the integrated circuitbonding area, and a width of the integrated circuit pad is greater thana width of the extending portion, wherein the width of the integratedcircuit pad is in a range from 3 μm to 20 μm.
 19. The manufacturingmethod of the display device as claimed in claim 15, wherein theflexible circuit board further comprises an insulating layer disposed inthe wiring area, and the insulating layer covers the conductive wires.20. The manufacturing method of the display device as claimed in claim14, wherein a thickness of at least one of the spacers is greater than athickness of the at least one of the conductive wires adjacent to the atleast one of the spacers.